U.S. patent number 10,051,223 [Application Number 15/620,972] was granted by the patent office on 2018-08-14 for photoelectric conversion apparatus and camera.
This patent grant is currently assigned to Canon Kabushiki Kaisha. The grantee listed for this patent is CANON KABUSHIKI KAISHA. Invention is credited to Tatsuya Ryoki, Kazuhiro Saito, Takanori Yamashita, Yoshikazu Yamazaki.
United States Patent |
10,051,223 |
Yamashita , et al. |
August 14, 2018 |
Photoelectric conversion apparatus and camera
Abstract
A photoelectric conversion apparatus having a first substrate
and a second substrate overlaid on each other and including
electrically conductive portions is provided. The first substrate
includes a photoelectric conversion element, a first portion
configured to form part of a first surface, a second portion which
is included in an electrically conductive pattern closest to the
first portion, and a third portion which is included in an
electrically conductive pattern second closest to the first
portion. The second substrate includes a fourth portion configured
to form part of a second surface, and a circuit. In a planar view
with respect to the first surface, an area of the first portion is
smaller than an area of the second portion and larger than an area
of a portion of the third portion overlaying the second
portion.
Inventors: |
Yamashita; Takanori (Hachioji,
JP), Saito; Kazuhiro (Tokyo, JP), Ryoki;
Tatsuya (Kawasaki, JP), Yamazaki; Yoshikazu
(Sagamihara, JP) |
Applicant: |
Name |
City |
State |
Country |
Type |
CANON KABUSHIKI KAISHA |
Tokyo |
N/A |
JP |
|
|
Assignee: |
Canon Kabushiki Kaisha (Tokyo,
JP)
|
Family
ID: |
60808071 |
Appl.
No.: |
15/620,972 |
Filed: |
June 13, 2017 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20180007305 A1 |
Jan 4, 2018 |
|
Foreign Application Priority Data
|
|
|
|
|
Jun 30, 2016 [JP] |
|
|
2016-131041 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L
27/1461 (20130101); H04N 5/64 (20130101); H04N
5/37455 (20130101); H04N 5/335 (20130101); H01L
27/14612 (20130101); H01L 27/14603 (20130101); H01L
27/14683 (20130101) |
Current International
Class: |
H04N
3/14 (20060101); H04N 5/3745 (20110101); H01L
27/146 (20060101); H04N 5/335 (20110101); H04N
5/64 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
Other References
US. Appl. No. 15/630,013, filed Jun. 22, 2017 (First Named
Inventor: Kazuhiro Saito). cited by applicant.
|
Primary Examiner: Tran; Sinh
Assistant Examiner: Gebriel; Selam
Attorney, Agent or Firm: Fitzpatrick, Cella, Harper &
Scinto
Claims
What is claimed is:
1. A photoelectric conversion apparatus having a first substrate
and a second substrate overlaid on each other such that a first
surface of the first substrate and a second surface of the second
substrate are brought into contact with each other, wherein the
first substrate includes: a photoelectric conversion element, a
first electrically conductive portion configured to form part of
the first surface, a second electrically conductive portion which
is included in an electrically conductive pattern closest to the
first electrically conductive portion and is electrically connected
to the first electrically conductive portion, and a third
electrically conductive portion which is included in an
electrically conductive pattern second closest to the first
electrically conductive portion and to which a signal generated in
the photoelectric conversion element is transmitted, wherein the
second substrate includes: a fourth electrically conductive portion
configured to form part of the second surface and electrically
connected to the first electrically conductive portion, and a
circuit electrically connected to the fourth electrically
conductive portion and configured to process the signal generated
in the photoelectric conversion element, and wherein in a planar
view with respect to the first surface of the first substrate, an
area of the first electrically conductive portion is smaller than
an area of the second electrically conductive portion and larger
than an area of a portion of the third electrically conductive
portion overlaying the second electrically conductive portion.
2. The apparatus according to claim 1, wherein in the planar view
with respect to the first surface of the first substrate, the area
of the first electrically conductive portion is larger than the
area of the third electrically conductive portion.
3. The apparatus according to claim 1, wherein the first substrate
further includes: a floating diffusion, a transfer transistor
configured to transfer a signal from the photoelectric conversion
element to the floating diffusion, and an amplification transistor
configured to amplify the signal transferred to the floating
diffusion, and wherein the first electrically conductive portion,
the second electrically conductive portion, and the third
electrically conductive portion form the same electrical node as an
output node of the amplification transistor.
4. The apparatus according to claim 3, wherein in the planar view
with respect to the first surface of the first substrate, the first
electrically conductive portion, the second electrically conductive
portion, and the third electrically conductive portion overlay the
floating diffusion.
5. The apparatus according to claim 3, wherein the first substrate
further includes a plurality of plugs configured to connect the
second electrically conductive portion and the third electrically
conductive portion to each other.
6. The apparatus according to claim 1, wherein the first substrate
further includes: a floating diffusion, a transfer transistor
configured to transfer a signal from the photoelectric conversion
element to the floating diffusion, a fifth electrically conductive
portion which is included in the electrically conductive pattern
closest to the first electrically conductive portion and is
electrically connected to a gate of the transfer transistor, and a
sixth electrically conductive portion configured to form part of
the first surface and electrically connected to the fifth
electrically conductive portion, wherein the second substrate
includes: a driving circuit configured to generate a signal for
driving the transfer transistor, a seventh electrically conductive
portion configured to form part of the second surface and
electrically connected to the sixth electrically conductive
portion, and an eighth electrically conductive portion which is
included in an electrically conductive pattern closest to the
fourth electrically conductive portion and is electrically
connected to the seventh electrically conductive portion, and to
which the signal from the driving circuit is transmitted, wherein
the sixth electrically conductive portion and the seventh
electrically conductive portion electrically connected to each
other form a connecting portion, and wherein the fifth electrically
conductive portion and the eighth electrically conductive portion
are electrically connected to each other by a plurality of
connecting portions.
7. The apparatus according to claim 3, wherein the first substrate
further includes a reset transistor configured to reset a voltage
of the floating diffusion.
8. The apparatus according to claim 1, wherein the first substrate
includes a plurality of unit cells each including the photoelectric
conversion element, the first electrically conductive portion, the
second electrically conductive portion, and the third electrically
conductive portion, and wherein the second substrate further
includes a signal line which is included in an electrically
conductive pattern closest to the fourth electrically conductive
portion and is electrically connected to the third electrically
conductive portion of each of the plurality of unit cells.
9. The apparatus according to claim 1, wherein an electrically
conductive pattern of the second substrate closest to the fourth
electrically conductive portion further includes a plurality of
ground lines, and wherein an electrically conductive pattern of the
second substrate second closest to the fourth electrically
conductive portion further includes an eighth electrically
conductive portion electrically connected to each of the plurality
of ground lines.
10. The apparatus according to claim 1, wherein the first substrate
includes a first semiconductor layer, wherein the second substrate
includes a second semiconductor layer, wherein the first
electrically conductive portion and the fourth electrically
conductive portion are provided between the first semiconductor
layer and the second semiconductor layer, and wherein the second
electrically conductive portion and the third electrically
conductive portion are provided between the first electrically
conductive portion and the first semiconductor layer.
11. A camera comprising: a photoelectric conversion apparatus
having a first substrate and a second substrate overlaid on each
other such that a first surface of the first substrate and a second
surface of the second substrate are brought into contact with each
other; and a signal processing unit configured to process a signal
obtained by the photoelectric conversion apparatus, wherein the
first substrate includes: a photoelectric conversion element, a
first electrically conductive portion configured to form part of
the first surface, a second electrically conductive portion which
is included in an electrically conductive pattern closest to the
first electrically conductive portion and is electrically connected
to the first electrically conductive portion, and a third
electrically conductive portion which is included in an
electrically conductive pattern second closest to the first
electrically conductive portion and to which a signal generated in
the photoelectric conversion element is transmitted, wherein the
second substrate includes: a fourth electrically conductive portion
configured to form part of the second surface and electrically
connected to the first electrically conductive portion, and a
circuit electrically connected to the fourth electrically
conductive portion and configured to process the signal generated
in the photoelectric conversion element, and wherein in a planar
view with respect to the first surface of the first substrate, an
area of the first electrically conductive portion is smaller than
an area of the second electrically conductive portion and larger
than an area of a portion of the third electrically conductive
portion overlaying the second electrically conductive portion.
Description
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a photoelectric conversion
apparatus and a camera.
Description of the Related Art
Japanese Patent Laid-Open No. 2012-15277 proposes an image
capturing apparatus formed by overlaying two substrates on each
other. A pad is formed on one surface of each substrate, and the
pads on both the substrates are brought into contact with each
other, electrically connecting a circuit formed on one substrate
and a circuit formed on the other substrate to each other.
SUMMARY OF THE INVENTION
Japanese Patent Laid-Open No. 2012-15277 does not describe the
two-dimensional layouts of pads and a wiring layer. An aspect of
the present invention provides a novel two-dimensional layout in a
photoelectric conversion apparatus formed by overlaying two
substrates on each other.
According to some embodiments, a photoelectric conversion apparatus
in which a first substrate and a second substrate are overlaid on
each other such that a first surface of the first substrate and a
second surface of the second substrate are brought into contact
with each other is provided. The first substrate includes a
photoelectric conversion element, a first electrically conductive
portion configured to form part of the first surface, a second
electrically conductive portion which is included in an
electrically conductive pattern closest to the first electrically
conductive portion and is electrically connected to the first
electrically conductive portion, and a third electrically
conductive portion which is included in an electrically conductive
pattern second closest to the first electrically conductive portion
and to which a signal generated in the photoelectric conversion
element is transmitted. The second substrate includes a fourth
electrically conductive portion configured to form part of the
second surface and electrically connected to the first electrically
conductive portion, and a circuit electrically connected to the
fourth electrically conductive portion and configured to process
the signal generated in the photoelectric conversion element. In a
planar view with respect to the first surface of the first
substrate, an area of the first electrically conductive portion is
smaller than an area of the second electrically conductive portion
and larger than an area of a portion of the third electrically
conductive portion overlaying the second electrically conductive
portion.
Further features of the present invention will become apparent from
the following description of exemplary embodiments (with reference
to the attached drawings).
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A and 1B are block diagrams for explaining an example of the
arrangement of an image capturing apparatus according to some
embodiments;
FIG. 2 is an equivalent circuit diagram for explaining an example
of a unit cell of the image capturing apparatus in FIGS. 1A and
1B;
FIGS. 3A to 3C are views for explaining an example of the sectional
structure of the image capturing apparatus in FIGS. 1A and 1B;
FIGS. 4A to 4D are views for explaining an example of each
two-dimensional layout of one substrate of the image capturing
apparatus in FIGS. 1A and 1B; and
FIGS. 5A and 5B are views for explaining an example of each
two-dimensional layout of the other substrate of the image
capturing apparatus in FIGS. 1A and 1B.
DESCRIPTION OF THE EMBODIMENTS
Embodiments of the present invention will be described below with
reference to the accompanying drawings. The same reference numerals
denote the same elements throughout the various embodiments, and a
repetitive explanation will be omitted. Also, the embodiments can
be changed and combined as needed. The present invention is applied
to, for example, a solid-state image capturing apparatus. In
addition, however, the present invention is also applicable to a
photoelectric conversion apparatus aiming at anything other than
image capturing. The present invention can also be used for, for
example, an application such as distance measurement or light
amount measurement. Some embodiments of the present invention will
be described below by taking the solid-state image capturing
apparatus as an example.
An example of the arrangement of a solid-state image capturing
apparatus 100 according to one embodiment of the present invention
will be described with reference to FIGS. 1A and 1B. The
solid-state image capturing apparatus 100 is formed by overlaying a
substrate S1 shown in FIG. 1A and a substrate S2 shown in FIG. 1B
on each other. The substrate S1 includes a pixel array 10. The
pixel array 10 includes a plurality of unit cells UNT arranged
along a predetermined surface. The plurality of unit cells UNT are
arranged so as to form a plurality of rows and a plurality of
columns. The pixel array 10 can include the plurality of unit cells
UNT which form the first group (for example, odd-numbered columns)
and the plurality of unit cells UNT which form the second group
(for example, even-numbered columns). Each of the plurality of unit
cells UNT includes a photoelectric conversion element. Accordingly,
the pixel array 10 can include a plurality of photoelectric
conversion elements which form the first group and a plurality of
photoelectric conversion elements which form the second group.
The substrate S2 includes, for example, A/D conversion circuits
(ADCU) 31 and 32, parallel/serial conversion circuits (PSD) 41 and
42, a vertical scanning circuit 20, a processing circuit (DSP) 70,
a timing generation circuit (TG) 80, and a clock generation circuit
(CGEN) 90.
The A/D conversion circuit 31 performs A/D conversion on a
plurality of signals respectively output from the plurality of unit
cells UNT which form the first group of the pixel array 10 to
generate a plurality of digital signals. The A/D conversion circuit
32 performs A/D conversion on a plurality of signals respectively
output from the plurality of unit cells UNT which form the second
group of the pixel array 10 to generate a plurality of digital
signals.
The parallel/serial conversion circuit 41 performs parallel/serial
conversion on the plurality of digital signals from the A/D
conversion circuit 31 to output serial signals. The parallel/serial
conversion circuit 42 performs parallel/serial conversion on the
plurality of digital signals from the A/D conversion circuit 32 to
output serial signals. The parallel/serial conversion circuits 41
and 42 can include horizontal scanning circuits.
The vertical scanning circuit 20 is a driving circuit which
generates control signals for driving transfer transistors of the
plurality of rows in the pixel array 10. More specifically, the
vertical scanning circuit 20 selects (activates) a plurality of
control signals corresponding to the plurality of rows,
respectively, of the pixel array 10 in a predetermined order. The
vertical scanning circuit 20 can include, for example, a scanning
circuit (SC) 21 formed by a shift register or the like, and a
buffer (BUF) 22 which buffers signals output from the scanning
circuit 21 and generates a plurality of control signals.
The processing circuit (DSP) 70 is formed by a digital signal
processor, and processes (for example, noise reduction, color
processing, correction, or compression) serial signals supplied
from the parallel/serial conversion circuits 41 and 42. The timing
generation circuit (TG) 80 generates, based on clock signals
supplied from the clock generation circuit (CGEN) 90, control
signals for controlling the vertical scanning circuit 20, the A/D
conversion circuits 31 and 32, the parallel/serial conversion
circuits 41 and 42, and the processing circuit 70. The clock
generation circuit 90 includes, for example, a DLL (Delay Locked
Loop), and generates clock signals which are synchronized with
externally supplied clock signals and supplies them to the timing
generation circuit 80.
A broken line 10' of FIG. 1B indicates a position of the perimeter
of the pixel array 10 when the substrate S1 and the substrate S2
are stacked. As shown in FIG. 1B, at least a part of the pixel
array 10 and at least a part of the processing circuit 70 are
overlaid. Moreover, at least the part of the pixel array 10 and at
least a part of the clock generation circuit 90 are overlaid.
The unit cells UNT of FIGS. 1A and 1B will now be described in
detail with reference to FIG. 2. FIG. 2 is an equivalent circuit
diagram showing one unit cell UNT. The unit cell UNT includes two
photoelectric conversion elements PD1 and PD2, two transfer
transistors TTX1 and TTX2, a floating diffusion FD, a reset
transistor TRES, and an amplification transistor TAMP.
The photoelectric conversion element PD1 is, for example, a
photodiode, and generates and accumulates charges corresponding to
incident light. Values corresponding to these charges form pixels
in an image obtained by the solid-state image capturing apparatus
100. The photoelectric conversion element PD1 is connected to the
floating diffusion FD via the transfer transistor TTX1. A control
signal .PHI.Tx1 is supplied from the vertical scanning circuit 20
of FIGS. 1A and 1B to the gate of the transfer transistor TTX1.
ON/OFF of the transfer transistor TTX1 is switched in accordance
with the level of the control signal .PHI.Tx1. When the transfer
transistor TTX1 is turned on, a charge signal is transferred from
the photoelectric conversion element PD1 to the floating diffusion
FD. The transferred charge signal is converted into a voltage
signal in the floating diffusion FD. The photoelectric conversion
element PD2, the transfer transistor TTX2, and a control signal
.PHI.Tx2 are similar to the photoelectric conversion element PD1,
the transfer transistor TTX1, and the control signal .PHI.Tx1. In
an example of FIG. 2, the two photoelectric conversion elements PD1
and PD2 share the floating diffusion FD. Instead of this, in each
unit cell UNT, only one photoelectric conversion element may be
connected to one floating diffusion FD, or three or more (for
example, four) photoelectric conversion elements may share the
floating diffusion FD.
The floating diffusion FD is further connected to a voltage source
Vd via the reset transistor TRES. A control signal .PHI.Res is
supplied from the vertical scanning circuit 20 of FIGS. 1A and 1B
to the gate of the reset transistor TRES. ON/OFF of the reset
transistor TRES is switched in accordance with the level of the
control signal .PHI.Res. When the reset transistor TRES is turned
on, the voltage of the floating diffusion FD is reset by a voltage
supplied from the voltage source Vd. When the reset transistor TRES
is turned off, the voltage of the floating diffusion FD enters a
floating state.
The floating diffusion FD is further connected to the gate of the
amplification transistor TAMP. One main electrode (for example, the
drain) of the amplification transistor TAMP is connected to the
voltage source Vd. The other main electrode (for example, the
source) of the amplification transistor TAMP is connected to a
signal line SIG. The amplification transistor TAMP forms a source
follower circuit together with a current source (not shown)
connected to the signal line SIG. More specifically, the
amplification transistor TAMP amplifies a signal transferred from
the photoelectric conversion element PD1 or the photoelectric
conversion element PD2 to the floating diffusion FD and transmits
the amplified signal to the signal line SIG. A voltage supplied to
the reset transistor TRES can take VH and VL serving as a potential
lower than VH. The potential of the floating diffusion FD becomes
relatively high when the reset transistor TRES is turned on in a
state in which VH is supplied. The potential of the floating
diffusion FD becomes relatively low when the reset transistor TRES
is turned on in a state in which VL is supplied. The pixels enter
an unselected state in a state in which the potential is relatively
low. The pixels enter a selected state in a state in which the
potential is relatively high. A specific pixel can be set in the
selected state by thus controlling the potential of the floating
diffusion. Instead of this, the specific pixel may be set in the
selected state by arranging a selection transistor between the
amplification transistor TAMP and the signal line SIG.
The sectional structure of the solid-state image capturing
apparatus 100 in FIGS. 1A and 1B will now be described with
reference to FIGS. 3A to 3C. FIGS. 3A to 3C place focus on, of the
solid-state image capturing apparatus 100, the structure of each
unit cell UNT and the wiring structure for supplying a signal to
the gate of the transfer transistor TTX1. FIG. 3B places focus on a
portion of FIG. 3A surrounded by a broken line 301. FIG. 3C places
focus on a portion of FIG. 3A surrounded by a broken line 302.
FIGS. 3A to 3C do not correspond to a two-dimensional layout in
each of FIGS. 4A to 4D to be described later in order to give a
higher priority to an explanation of the connection relationship
among respective elements and the positional relationship among the
views in a vertical direction. The substrate S1 and the substrate
S2 are overlaid on each other such that one surface F1 (a lower
surface in FIG. 3A) of the substrate S1 and one surface F2 (an
upper surface in FIG. 3A) of the substrate S2 face each other.
The substrate S1 includes a semiconductor region 310 and an
insulator region 320. The semiconductor region 310 is a region
mainly formed by a semiconductor such as silicon. The semiconductor
region 310 can include an insulator portion such as an element
isolation region (not shown). The insulator region 320 is a region
mainly formed by an insulator such as silicon oxide or silicon
nitride. The insulator region 320 can include conductors such as
electrically conductive patterns and plugs to be described
later.
The semiconductor region 310 includes impurity regions 311 to 314
on a side close to the surface F1. The impurity region 311 forms
the photoelectric conversion element PD1. The impurity region 312
forms the floating diffusion FD. The impurity region 313 forms one
main electrode (for example, the drain) of the reset transistor
TRES and the other main electrode (for example, the drain) of the
amplification transistor TAMP. The impurity region 314 forms the
other main electrode (for example, the source) of the amplification
transistor TAMP. The solid-state image capturing apparatus 100
includes a microlens ML on a surface of the substrate S1 on a side
opposite to the surface F1. The microlens ML is arranged at a
position where light from the upper side of FIG. 3A is condensed to
the impurity region 311.
The insulator region 320 includes gates G1 to G3 near the interface
between the semiconductor region 310 and the insulator region 320.
The insulator region 320 further includes a gate insulating film
(not shown) between the semiconductor region 310 and the gates G1
to G3. The gate G1 is the gate of the transfer transistor TTX1. The
gate G2 is the gate of the reset transistor TRES. The gate G3 is
the gate of the amplification transistor TAMP.
The insulator region 320 further includes a plurality of
electrically conductive patterns WP1 to WP4 and a plurality of
plugs which connect these electrically conductive patterns to each
other. In this embodiment, the insulator region 320 includes four
electrically conductive patterns. However, the number of
electrically conductive patterns may be larger or smaller than
this. The electrically conductive pattern WP4 is closest to the
surface F1 out of the plurality of electrically conductive patterns
WP1 to WP4. The electrically conductive pattern WP3 is the second
closest to the surface F1 out of the plurality of electrically
conductive patterns WP1 to WP4.
The substrate S2 includes a semiconductor region 360 and an
insulator region 370. The semiconductor region 360 is a region
mainly formed by a semiconductor such as silicon. The semiconductor
region 360 can include an insulator portion such as an element
isolation region (not shown). The insulator region 370 is a region
mainly formed by an insulator such as silicon oxide or silicon
nitride. The insulator region 370 can include conductors such as
electrically conductive patterns and plugs to be described
later.
The semiconductor region 360 includes, for example, an impurity
region of a transistor in each circuit formed in the substrate S2.
The insulator region 370 further includes the gate of the
transistor, a plurality of electrically conductive patterns WP5 to
WP9, and a plurality of plugs which connect these electrically
conductive patterns to each other. In this embodiment, the
insulator region 370 includes five electrically conductive
patterns. However, the number of electrically conductive patterns
may be larger or smaller than this. The electrically conductive
pattern WP5 is closest to the surface F2 out of the plurality of
electrically conductive patterns WP5 to WP9. The electrically
conductive pattern WP6 is the second closest to the surface F2 out
of the plurality of electrically conductive patterns WP5 to
WP9.
The portion surrounded by the broken line 301 will now be described
in detail with reference to FIG. 3B. The portion shown in FIG. 3B
forms part of a transmission path of a signal supplied from the
vertical scanning circuit 20 of FIGS. 1A and 1B to the gate G1
(that is, the gate of the transfer transistor TTX1). The insulator
region 320 of the substrate S1 further includes an electrically
conductive portion 324 and an electrically conductive portion 325.
Each of the electrically conductive portion 324 and the
electrically conductive portion 325 forms part of the surface F1 of
the substrate S1. In this specification, the electrically
conductive patterns are formed inside the insulator regions of the
substrates, and an electrically conductive portion which forms part
of the outer surface of each substrate is not an electrically
conductive pattern. The electrically conductive pattern WP4
includes an electrically conductive portion 321. The electrically
conductive portion 321 is electrically connected to the gate G1 of
the transfer transistor TTX1. The electrically conductive portion
321 and the electrically conductive portion 324 are electrically
connected to each other by a plug 322. The electrically conductive
portion 321 and the electrically conductive portion 325 are
electrically connected to each other by a plug 323.
The insulator region 370 of the substrate S2 further includes an
electrically conductive portion 326 and an electrically conductive
portion 327. Each of the electrically conductive portion 326 and
the electrically conductive portion 327 forms part of the surface
F2 of the substrate S2. The electrically conductive pattern WP5
includes an electrically conductive portion 330. A signal from the
vertical scanning circuit 20 is transmitted to the electrically
conductive portion 330. The electrically conductive portion 330 and
the electrically conductive portion 326 are electrically connected
to each other by a plug 328. The electrically conductive portion
330 and the electrically conductive portion 327 are electrically
connected to each other by a plug 329.
The electrically conductive portion 324 and the electrically
conductive portion 326 are in contact with each other. The
electrically conductive portion 324 and the electrically conductive
portion 326 form one connecting portion configured to electrically
connect the two substrates S1 and S2 to each other. Moreover, the
electrically conductive portion 325 and the electrically conductive
portion 327 are in contact with each other, and the electrically
conductive portion 325 and the electrically conductive portion 327
form another connecting portion configured to electrically connect
the two substrates S1 and S2 to each other. As shown in FIG. 3B,
the electrically conductive portion 321 and the electrically
conductive portion 330 are electrically connected to each other by
two separated connecting portions. The number of connecting
portions which electrically connect the electrically conductive
portion 321 and the electrically conductive portion 330 to each
other may be one or the plural number other than two.
The portion surrounded by the broken line 302 will now be described
in detail with reference to FIG. 3C. The portion shown in FIG. 3C
forms part of a transmission path of a signal supplied from the
impurity region 314 (that is, the source of the transfer transistor
TTX1) to the processing circuit 70 of FIGS. 1A and 1B.
The insulator region 320 of the substrate S1 further includes an
electrically conductive portion 336. The electrically conductive
portion 336 forms part of the surface F1 of the substrate S1. The
electrically conductive pattern WP3 includes an electrically
conductive portion 331. The electrically conductive portion 331 is
electrically connected to the impurity region 314, and a signal
generated in the photoelectric conversion element PD1 is
transmitted to the electrically conductive portion 331. The
electrically conductive pattern WP4 includes an electrically
conductive portion 334. The electrically conductive portion 331 and
the electrically conductive portion 334 are connected to each other
by two plugs 332 and 333. The electrically conductive portion 334
and the electrically conductive portion 336 are connected to each
other by a plug 335.
The insulator region 370 of the substrate S2 further includes an
electrically conductive portion 337. The electrically conductive
portion 337 forms part of the surface F2 of the substrate S2. The
electrically conductive pattern WP5 includes a signal line 339. The
electrically conductive portion 337 and the signal line 339 are
electrically connected to each other by a plug 338. The signal line
339 is electrically connected to the A/D conversion circuit 31.
The electrically conductive portion 336 and the electrically
conductive portion 337 are in contact with each other. The
electrically conductive portion 336 and the electrically conductive
portion 337 form one connecting portion configured to electrically
connect the two substrates S1 and S2 to each other. The respective
electrically conductive portions and plugs shown in FIG. 3C form
the same electrical node as the output node (impurity region 314)
of the amplification transistor TAMP.
An example of the two-dimensional layout of the unit cell UNT of
the solid-state image capturing apparatus 100 in FIGS. 1A and 1B
will now be described with reference to each of FIGS. 4A to 4D.
Each of FIGS. 4A to 4D shows the layout in a planar view with
respect to the surface F1 of the substrate S1. The impurity regions
311 to 314, an impurity region 411, and the gates G1 to G4 are
arranged as shown in FIG. 4A. The impurity region 411 forms the
photoelectric conversion element PD2. The gate G4 is the gate of
the transfer transistor TTX2. FIG. 4B is a view obtained by adding
the electrically conductive portion 331, and the plugs 332 and 333
to FIG. 4A. The electrically conductive portion 331 is arranged so
as to overlay the impurity regions 312 to 314. FIG. 4C is a view
obtained by adding the electrically conductive portion 334 to FIG.
4B. In order to clarify a positional relationship, only the contour
of the electrically conductive portion 334 is shown. The
electrically conductive portion 334 is arranged so as to overlay
the impurity region 312 and the electrically conductive portion
331.
FIG. 4D is a view obtained by adding the electrically conductive
portion 336 and the plug 335 to FIG. 4C. In order to clarify a
positional relationship, only the contours of the electrically
conductive portion 336 and the plug 335 are shown. The electrically
conductive portion 336 is arranged so as to overlay the impurity
region 312, the electrically conductive portion 331, and the
electrically conductive portion 334.
In the planar view with respect to the surface F1 of the substrate
S1, the area of the electrically conductive portion 336 is smaller
than the area of the electrically conductive portion 334 and larger
than the area of a portion of the electrically conductive portion
331 overlaying the electrically conductive portion 334. Further,
the area of the electrically conductive portion 334 may become
larger than the area of the electrically conductive portion 331 in
the planar view with respect to the surface F1 of the substrate S1
by making the electrically conductive portion 334 larger than that
shown in each of FIGS. 4A to 4D.
An example of the two-dimensional layout of the substrate S2 at
positions corresponding to the unit cells UNT of the solid-state
image capturing apparatus 100 in FIGS. 1A and 1B will now be
described with reference to FIGS. 5A and 5B. Each of FIGS. 5A and
5B shows the layout in a planar view with respect to the surface F2
of the substrate S2. FIG. 5A shows the two-dimensional layout of
the electrically conductive portion 337, the plug 338, and the
electrically conductive portion included in the electrically
conductive pattern WP5. The electrically conductive portion
included in the electrically conductive pattern WP5 includes the
signal line 339, a signal line 502, a ground line 501, and a ground
line 503. The signal line 339 is electrically connected to the
respective electrically conductive portions 331 of the plurality of
unit cells UNT arranged in a column direction. Accordingly, signals
generated in the photoelectric conversion elements PD1 and PD2 of
the plurality of unit cells UNT are transmitted to the signal line
339. A ground voltage is supplied to each of the ground line 501
and the ground line 503.
FIG. 5B is a view obtained by adding an electrically conductive
portion 504, a plug 505, and a plug 506 to FIG. 5A. The
electrically conductive pattern WP6 includes the electrically
conductive portion 504. The plug 505 and the plug 506 are
respectively electrically connected to the electrically conductive
portion 504 and the ground line 501. As shown in FIG. 5B, the
electrically conductive portion 504 extends in a horizontal
direction, and is electrically connected to the plurality of ground
lines 501 and 503.
In the above-described embodiment, the photoelectric conversion
elements PD1 and PD2, the transfer transistors TTX1 and TTX2, the
reset transistor TRES, and the amplification transistor TAMP are
formed in the substrate S1. Instead of this, at least one of the
reset transistor TRES and the amplification transistor TAMP may be
formed not in the substrate S1 but in the substrate S2.
In the above-described embodiment, the electrically conductive
portion 336 and the electrically conductive portion 334 are
connected to each other by the plug 335. Instead of this, the
electrically conductive portion 336 and the electrically conductive
portion 334 may be connected to each other directly (that is,
brought into contact with each other) without using the plug 335.
The plugs 322, 323, 328, 329, and 338 may be omitted in the same
manner.
As an application of the solid-state image capturing apparatus 100
according to each embodiment described above, a camera in which the
solid-state image capturing apparatus 100 is assembled will
exemplarily be described below. The concept of the camera includes
not only an apparatus mainly aiming at shooting but also an
apparatus (for example, a personal computer, a portable terminal,
an automobile, or the like) accessorily having a shooting function.
The camera may be a module part such as a camera head. The camera
includes the solid-state image capturing apparatus 100 according to
the present invention exemplified as the above-described
embodiments, and a signal processing unit which processes a signal
output from this solid-state image capturing apparatus 100. This
processing unit can include, for example, a processor which
processes digital data based on the signal obtained in the
solid-state image capturing apparatus 100. An A/D converter
configured to generate this digital data may be provided in a
semiconductor substrate of the solid-state image capturing
apparatus 100 or another semiconductor substrate.
While the present invention has been described with reference to
exemplary embodiments, it is to be understood that the invention is
not limited to the disclosed exemplary embodiments. The scope of
the following claims is to be accorded the broadest interpretation
so as to encompass all such modifications and equivalent structures
and functions.
This application claims the benefit of Japanese Patent Application
No. 2016-131041, filed Jun. 30, 2016, which is hereby incorporated
by reference herein in its entirety.
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